Koolance EXT-440CU Liquid Cooling System with CPU-380I Water Block Review

Cooler Comparison Testing

Cooler Testing Methods

To best gage the quality of the system coolers under review, system CPU temperature and cooling system audio measurements were taken with the CPU idle and under load. To replicate CPU idle conditions, the system was rebooted and allowed to sit idle for 10 minutes. To replicate a stress system load on the Z77-based system, a combination of LinX and FurMark were run over a 30 minute period with LinX running for 500 loops with Memory set to All and FurMark running at 1280×1024 resolution and 2x MSAA in stress test mode. For the Z87-based system testing, Aida64 System Stability Test was used in conjunction with FurMark for 30 minutes per run. After each run, the system was shut down and allowed to rest for 10 minutes to cool down. Then the CPU cooler was removed, cleaned, and remounted to the CPU with fresh thermal paste applied. This procedure was repeated a total of nine times for each cooler – three times for the stock speed runs on the Z77 and Z87-based systems, and 3 times for the overclocked speed runs on the Z77-based system.

Temperature measurements were taken directly from the CPU thermistors using RealTemp (the newer Tech|Inferno edition). For the Z77-based systems, the highest recorded value for idle and load temperature were used for the run. Because of the volatile nature of the Haswell thermistor readings, the Z87-based system temperatures were measured in a different manner. For idle temperatures, the highest recorded value was used for the run. For load temperatures, a series of three values were notated: the average (high and low) across all cores, the average (high and low) across the single highest core, and the high temperature.

To adequately measure the Koolance EXT-440CU with CPU-380I block kit performance, performance testing was done for all scenarios under three operation conditions – high speed, medium speed, and low speed. High speed settings consisted of the EXT-440CU unit fan and pump speeds set to 10, medium speed tests were done with fan and pump speed set to 5, and low speed tests completed with fan and pump speed set to 1. Both the fan and pump speeds were manually set between test runs using the control interface integrated into the EXT-440CU's front panel.

Note that the temperature values are reported as deltas rather than absolute temperatures with the delta value reported calculated as CPU temperature – ambient temperature. For all tests, room ambient temperature was maintained between 23-27C. Sound measurements of the system cooler where taken with the sound meter placed 3 feet away from the system with all other devices in the room silenced. The Sound Meter Pro applet on a Samsung Galaxy S3 mobile phone was used to measure decibel level.

Intel Z77-based Ivy Bridge System Testing

CPU Stock Speed Testing

The CPU stock speed testing was conducted with the BIOS defaults set (including enabling of the CPU-integrated graphics processor) with Turbo Mode disabled, equating to a 3.4GHz CPU speed, 1600MHz memory speed, and 100MHz base clock. The Intel Speedstep functionality remained enabled for the duration of the testing to get realistic CPU idle performance conditions.

With an Ivy Bridge CPU running at stock settings, the Koolance EXT-440CU with the CPU-380I block performed well within expectations, matching or beating the Corsair all-in-one unit but not quite beating out the XSPC unit. The more interesting fact here is the close grouping of the Koolance kit's performance numbers, indicating that the kit is not at all stressed with the heat load no matter how far you reduce the fan speed or pump speed levels.

CPU Overclocked Speed Testing

The CPU overclocked speed testing was conducted with known stable settings from a previous board review with Turbo Mode disabled, equating to a 4.4GHz CPU speed, 1960MHz memory speed, and 105MHz base clock. Also, the CPU-integrated graphics processor was disabled to reduce the processor heat generation. The Intel Speedstep functionality remained enabled for the duration of the testing to get realistic CPU idle performance conditions.

Board voltage settings were configured as follows:

• CPU Core Voltage – 1.2750
• CPU I/O Voltage – 1.150
• DRAM Voltage – 1.6255
• System Agent Voltage(SA) – 1.0850
• CPU PLL Voltage – 1.7500
• PCH 1.05 – 1.0995

The Ivy Bridge CPU at overclocked settings gives the Koolance kit a better run for the money with the performance gulf between it and the all-in-one Corsair cooler widening. At full speed, the Koolance kit is a mere 2C behind the XSPC kit. Also note that the spread between the high-speed and low-speed performance for the Koolance kit is larger than at stock settings, but remains only a difference of 4C.

Intel Z87-based Haswell System Testing

CPU Stock Speed Testing

The CPU stock speed testing was conducted with the BIOS defaults set for the CPU (including enabling of the CPU-integrated graphics processor) and Turbo Mode disabled, equating to a 3.4GHz CPU speed, 1600MHz memory speed, and 100MHz base clock. The Intel Speedstep functionality remained enabled for the duration of the testing to get realistic CPU idle performance conditions.

Here we really begin to see the performance potential of the Koolance kit with its performance at both full and mid-speed settings within 1-3C of the top performers. An oddity that surfaced in testing with the Haswell-based CPU was that the Koolance kit was unable to keep the system stable at minimum speeds setting (with the fan speed and pump speed set to 1). After about 10 minutes into the run, the Koolance unit would automatically increase the pump and fan speeds to compensate for increasingly elevated CPU temperatures. The behavior was not seen with the unit operating at the medium or high-speed settings.

CPU Overclocked Speed Testing

The CPU overclocked speed testing was conducted with known stable settings from a previous board review with Turbo Mode disabled, equating to a 4.68GHz CPU speed, 1780MHz memory speed, 4.0GHZ ring bus speed, and 167MHz base clock. Also, the CPU-integrated graphics processor was disabled to reduce the processor heat generation. The Intel Speedstep functionality remained enabled for the duration of the testing to get realistic CPU idle performance conditions.

Board voltage settings were configured as follows:

• CPU Core Voltage – 1.25 + 0.005
• VCCIN Voltage – 1.90
• DRAM Voltage – 1.55
• CPU Ring Voltage – 1.125 + 0.005
• CPU SA Voltage Offset – +0.100
• CPU IO Analogue Voltage Offset – +0.100
• CPU IO Digital Voltage Offset – +0.100
• PCH 1.05 Voltage – 1.120

The Haswell CPU-based tests with overclocked settings really pushed the Koolance kit to it performance limits, illustrating how well Koolance designed the EXT-440CU unit to scale with increased heat load. While the kit did not lead the performance numbers, it remained within 2-3C of the top performing units across all temperature groupings. The most interesting performance metric is the minimal temperature differences between the unit in high-speed mode versus medium-speed mode. You only see a 3-5C drop in performance by halving the fan and pump speeds. As stated previously, the Koolance unit was unable to complete the test with the Haswell processor in low speed mode.

Sound Testing

The sound performance of the EXT-440CU unit was surprising with its full-speed operating mode audible over other case fan noise, but still below that of a graphics card fan running full tilt. The sound scales as expected with operating speed reducing during medium and low-speed testing. At medium speeds, the unit is barely audible, while at low-speeds, the unit is whisper quiet.